GEMMA and Trinket are great when you want a tiny, low cost microcontroller to embed in your projects. One of the tradeoffs, however, is that they can’t send data back to the computer for debugging sensor values.

For instance, you want to make a pair of Firewalker sneakers with Gemma instead of Flora, but there’s no easy way to calibrate your Velostat step sensor since you can’t see the numerical value of the reading. I recommend keeping a FLORA around for this purpose, even if you port to GEMMA later.

But there’s a workaround-- you can use software serial and a modified console cable to debug values on Gemma. Let’s wire it up. You will need:

• GEMMA microcontroller
• console cable
• alligator clips
• soldering iron and solder
• wire strippers
• helping third hand tool

You can also use a spare Arduino Uno if you can't get your hand on a console cable-- check out the last page of this guide to learn how!